Patent GB-191410901-A (GB)
Title: A Mechanical Signalling Apparatus for use in Mines and other places.
Inventor: TRAWFORD BERNARD
IPC: B66B19/06
Filed: 1914-05-04
Granted: 1914-11-26
Abstract: 10,901. Trawford, B. May 4. Mechanical telegraphs. -Audible and visible signals are given in mines &c. by successive pulls of a rope acting on a lever A, each pull being signalled by a stroke on the bell a, Fig. 3, and the number of pulls indicated by the appearance of a numeral before a window d' in the casing d, Fig. 2. If the signal " 1 " is given, the lever A makes a single stroke and is returned by the coil spring 0. During the forward movement of the lever, the pawl B turns the ratchet - wheel C and shaft D against the tension of a coil spring M. A toothed sector G secured to the lever A engages with a rack H, so that the arm H<1> lifts the piston F of a dashpot E. This dash - pot has an adjustable outlet valve K, an air - inlet valve J, and a groove E<1> in the cylinder so as to afford free movement to the piston near the end of its downward stroke. The effect of lifting the dash-pot piston is to lock the ratchet-wheel C by means of the pawl L until the piston returns to its lowest point. A spring-pressed plunger pawl T in the shaft D engages with a projection in the sleeve Q, so that the sleeve Q, arm P, and plate P<1> bearing the numeral " 1 " are moved with the shaft D, the numeral " 1 " thus appearing at the window d<1>. A stop prevents any further movement of the sleeve Q. If further movement of the shaft D takes place, the plunger pawl T yields and passes the projection by means of which it actuates the sleeve. The sleeve Q and the exhibited signal " 1 " are held by a detent, of which the tail-piece V is shown in Fig. 2. Therefore, although the pawl L releases the shaft D after the interval determined by the dash-pot, the plate P' bearing the signal " 1 " remains exposed. The plate P<1> is released when the winding-engine is set in motion in response to the signal, the shaft Z being rotated from the engine so that a cam trips out the pawl V. If a signal involving two or more strokes on the bell is given, the shaft D is stepped round by one tooth of the ratchet-wheel C for each stroke. At the first stroke, the signal " 1 " is exhibited as already described, but the subsequent strokes take place at intervals less than is required to release the detent L, and the second and subsequent successive movements of the shaft D cause a sleeve S (tensioned by the coil spring Y) to be rotated through the medium of a stud U, the first movement of which takes place idly in a slot. The sleeve S carries the plate R on which the signals " 2 ", " 3 ", &c. are written, and the chosen signal is exhibited at the window d<1>. The sleeve S bears a cam S' which acts directly on the detent V so as to release the sleeve Q and plate P<1> as soon as signal " 2 " is exposed. The sleeve S also carries a ratchet-wheel S<2> which is held by the detent pawl X so that any signal exhibited remains exposed in spite of the ultimate return of the shaft D to normal position when the pawl L releases it. The detent X is withdrawn either by a cam on the shaft Z if the winding-engine is set in motion, or by the impact of the arm P on an extension X<1> of the detent X if the signal " 1 " is given subsequently to the signal " 2 " or " 3 ".